DESCRIPTION: The identification of novel bioactive compounds is becoming increasingly more difficult. Many potential sources have been screened numerous times, decreasing the possibility of finding additional, useful materials. One way to avoid this stumbling block is to identify novel microorganisms. One of the more fruitful places to find untested organisms is to search habitats that are largely unexplored but are known to include active microbial communities. This application proposes to screen extracts from organisms found in microbial mats in thermal waters and from fumaroles for antifungal activity. The two objectives in this Phase I application are: 1. To integrate a battery of screens to test samples for antifungal activity. These will include whole cell assays, in vitro enzyme screens and os-1 cell-wall screen; and 2. To test thermophilic organisms for antifungal activity. This work will identify organisms that produce antifungal antibiotics from previously unscreened environments. It is likely that these compounds will be novel and lead to new antifungal therapeutics.